Lead-testing machine



April 24, 192s. 1,667,109 P. E, GARLENT LEAD TESTING MACHINE Filed May 9, 1927 3 Sheets-Sheet 1 1311 .INH

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P, E. GARLENT LEAD TESTING MACHINE Filed May 9, 1927 5 Sheets-Sheet 2 1 .i It V i* W W um April 24, 192s. Y 1,667,109

- P. E.. GARLENT LEAD TESTING MACHINE Filed May 9, 1927 5 Sheets-Sheet 3 hsomeys.

Patented `Apr. l24, 1928.

UNITED STATES I '1,667,109 PATENT OFFICE.

PIERCE E. GARLENT, DETROIT, MICHIGAN, ASSIGNOR T0 THE' TIIKEN-DETROIT AXLE COMPANY, 0F DETRCIT, MICHIGAN, A CORPORATION 0F OHIO,

LEAD-TESTING MACHINE.

Application illed May 9, 1927. Serial No. 189,889.

This invention relates to lead testing machines and has for its principal objects to produce a machine that Will accurately determine errors in the lead ofscrews and'that can be adjusted to check the leads of Single or multiple thread screws. Another' object is to enable the machine to be set for any selected lead. Other objects are to provide means for measuring the pitch and the pressure angle of the thread and for checking the setting of the machine. The invention consists in the machine. and in lne parts and combinations of parts hereinafter described and claimed.

In the accompanying drawings which form part of this specification and wherein like symbols refer to like parts wherever they occur.

Fig. 1 is a plan View of a lead testing machine embodying my invention with the parts adjusted for gagmg the double thread worm shown mounted therein, a portion of the head stock bein shown in horizontal section to more cleay illustrate the invention' 2 is a fragmentary View of the head stock portion of the machine, showing the bottom slide plate adjusted for a Worm having a lea-d angle of degrees;

Fig. 3 is a front elevation of the machine with a portion of the head stock shown in I vertical section;

Fig. 4 is an end view of the machine;

Fig. 5 is a' vertical section on the line 5-5 in Fig. 3;

Fig. 6 is a vertical section on the line 6-6 in Fig.8;

a section on the line 7-7 in Fig. 8;

Fig. 8 parts shown in Figs. 6 and 7 looking at .right angles to the plane of the top surface thereof; and

'Fig 9 1s a'vertical section through the head-stock on the line 9-9 in Fig. 3. l

My lead testing machine comprises a carriage 1 slidable on longitudinal ways 2 provid-'ed therefor along "the top` of a bed` 3 supported on legs 4; The work'that is to be tested is shown in the form of a worm, which is rotatably supported between the opposed conical ends of two axially almed horizontally disposed dead centers 5 and 6,

' which extend lengthwise'of the carriage at the longitudinal renter line'thereof and areI is a fragmentary planv view of the4 mounted. respectively, in a head stock 7 located at one end of the carriage 1, and a tail stock 8 located at at the other end of said carriage. The dead center 5 has a press t in the small end of a bore in the head stock 7 and the dead center 6 is adj usted axially in the tail stock 8 by means of the usual hand wheel 9 and is clamped in the desired position of 'adjustment by means of the usual handle 10. As'shown in the drawing, the tail stock is slidable on longitudinal ways 11 provided therefor along the top of the carriage 1 and is clamped in the deslred position of sliding movement 'by means of al T-bolt 12 whose hea-d fits within a T-slot 13 provided therefor in the carriage. l

The mechanism for sliding the carriage 1 along the bed 3 preferably comprisesa horizontal shaft 14 jou'rnaled in a bearing 15in the front side of said carriageintermediate the head and 'tail stocks carried thereby. The shaft 14, which extends transversely of the longitudinal axis of the carriage, is provided atits outer end with a hand wheel 16 and at its inner end with a bevel gear 17. Said bevel gear 17 meshes with a similar gear 18 on one end of the horizontal shaft 19, whichfextends longitudinally of the carriage and isf-rotatably supported near its opposite ends in bearings 20 secured to the top of the carriage. The other end of the longitudinal shaft 19 is provided with a pinion 21 which meshes with gear teeth 22 formed in the peripheral surface of an index late or disk 23 sleeved onythe outer end of t 1e tubular spindle 24 of the head stock 7. Said head stock spindle 24 comprises a cylindrical sleeve which is rotatably supported on the dead'center 5 of the head stock and in bush ing or bearing sleeve 25 pressed in the large end ofthe bore within whose smaller. end

The rack 28 is screwed and doweled to the upper surface of avhorizontal slide plate 29, which. is' supported fer hormonal @balas slideway 36 formed in the upper surface of a horizontally disposed circular plate or disk 37 which rests flatwise in a recess 38 provided therefor-dn the upper surface of the bed. The disk 37 is provided at? its center with a depending spindle 39 which is journaled in a pocket bearing 40 provided therefor inthe bottom of the recess 38. As shown in the drawing, the axis of the rotary disk 37 intersects the axis of the head stock' spindle and is perpendicular thereto, the radial slideway 36 in the upper surface of said disk extends through its center and is terminated at each end by the peripheral edge thereof, the slide plate 35 carried by said disk is lsubstantially the. same length as the diameter thereof, and the trunnion 34 on said slide plate is preferably formed integral therewith and is located substantially midway of the length thereof.

Thel disk 37, which slidablysupports the lower slide plate35, is turned or rotated to vary the angular position of said slide plate with lrelation to vthe upper slide plate 29 preferably by meansv ofv a Worm 41 which meshes with teeth 42 cut in the peripheral surface of the disk. The worm 41 is carried on va horizontal worm shaft 43, which extends from side to side of the bed 3 with its ends rotatably supported in bearings 44 in the bedi3 and is rotated by means of a hand wheel 45 fixed to one end of said worm shaft.

`In order to set the bottom slide plate .35

. at an angle corresponding to the lead angle of the worm that is to be tested the machine is provided on each'side vof its longitudmal axis with a pair ot' upstanding pins 46 and 47 located, respectively, on the bed 3 and on the disk 37 which rotatably supports said bottom slide plate. Thus, with a certain spacing of the pins 46 and 47 a certain angular position of the bottom slide plate may be obtained. An accurate setting of the bottom slide plate may be readily obtained by means of a set of gaging devices in the formof links 48 provided with holes adapted to. fit the pins 46 and 47. The holes in each link are spaced diiferent distances apart; and a link which willset the bottom slide plate at air-angle corresponding to the lead angle of a worm has the lead of such worm stamped thereon. Thus, the operator, knowing the and uses said link to obtain an accurate settingof the bottom slide plate. As shown in the drawing a pair-of pins 46and 47 is located on each side of the machine to permit -the bottom slide plate to be set for checking right and left hand worms. Although the links 48, when in engagement with the pins 46 and 47, prevent rotation of the disk 37 and thus hold the bottom slide plate in the proper angular position, said disk mayl also be locked against rotation by means of T- bolts 49, which extend through holes in the brackets 95 of the bed l3 and have their heads located in arcuate T-slots 50 in said disk.

Rotatably supported on the projecting forward end of the rota-ry head stock spindle 24 adjacent to outer face ot the indexing disk 23 fixed thereon is a circular driving plate or disk 51 which is held on said spindle by means of jam nuts 52 threaded on the outer end of the dead center 5 of the head stock. The driving disk 51 is connected to and disconnected from the indexing disk 23 by means of a spring pressed indexing ,pin 53 slidable in a bracket 54 pivotally secured to the front face of said driving disk by means of a pivot screw 55. The bracket 54 may be swung on its securing screw 55 asa pivot to permit the spring pressed indexing pin 53 to enterany one of three holes 56, 57 and 58 which extend through the driving disk at equal distances from the pivotal axis of the bracket but at different distances from the spindle axis. The driving disk 51 is'connected with the indexing disk 23 by passing the indexing pin through one of the three holes 56, 57 and 58 in said driving disk y,and a registering hole" ot'Vone of three seriesv of circularly arranged holes 59, 60 and 6l in said indexing disk. The three series of holes in the indexing plate are arranged in circles concentric to each other and to the spindle axis and at a distance therefrom which will permit each series of such holes to be brought into register with one of the three holes in the driving disk. By this arrangement the worm driving disk 5l may be connected to the gear driven indexingdisk 23 by turning said driving diskto b ring one of the three holes therein into register with one of the holes ot'one 'of the three 'series oi holes in the indexing plate and then with the driving disk 5 1 for rotation therewith by means of an arm 63 which projects llo radially from one ,member of said clamping dog and has its free end secured to a bracket 64 rigidly secured to the front face of said driving disk. By this arrangement, the worm is forced to rotates with the driving disk when the same is connectedtto" the indexing disk. v

Secured to the rear sideof the base or bed 3 of the machine is'an upstanding bracket 65 which projects abovethe carriage 1 and teiniinates in a way 66 which extends longitudinally of vthe machine parallel to the longitudinal axis thereof and is disposed at an angle of about 45 degrees to the sui'- face of the carriage and is inclined towards the face of the carriage. v Rotatably supported within a longitudinal channel or groove 67 in the way 66 at the upper end of the bracket- 65 is a horizontal lead screw 68, which extends from end to end of the bracket parallel to the axes of the dead centers of the head and tail stocks and is rotated by means of a handle -68a fixed to one end of said screw, Slidably mounted on the way 66 at the top of the bracket is an indicator carriage 69 operatively connected with the lead screw 68 by means of a nut 70 formed integral with the lower end of a bolt 71- which projects upwardly through registering holes in the carriage and in a cylindrical pivot piece 72 rigidly secured on top of said carriage by means of a nut 73 on the upper end of said bolt. Mounted on the carriage 69 is a bracket member 74 whose base is provided with a cylindrical recess 7 5 which receives the cylindrical pivoted piece 7 2 on top of the carriage, whereby said bracket member is rotatable on said carriage. The pivoted bracket member 7 4 is 'clamped to the indicator carriage by T-bolts 76 whose heads are located in arcuate T- slots 77 provided therefor inthe top of said carriage and whoseshank portions extend upwardly through holes in the bracket mem'- ber 74 and are provided with nuts 78. By

this arrangement, the T-bolts 76 may be tightened to lock lthe pivotally mounted bracket member 74 in any desired angular position.

Mounted on a plate 79, which is slidable transversely of the worm on a way 80 provided theretor on the upper sui-face of the bracket 74 pivoted on the indicator cai'- riage 69, is an indicator 81. Said indicator is provided with a radially disposed longitudinally slidable stem 82 for actuating its .indicating mechanism and hasa handle 83 for limiting the outward sliding move# ment of said stein. Mounted on the indicator vcasing forv swinging movement about the axis of the indicator stem 82 is an arm 85 which 1s clamped 1u any desired posij tion .of its" swinging movement by means ofa knurled collet85a. Pivotally supported on the-arm 85 is a bent contact lever 86, one

arm of which is adapted to engage one side ot' the thread of the worm and the other arm of which is adapted to bear against the outer end of the stem 82 of the indicator and thus actuate the indicating mechanism thereof. 'lhe indicator 81 is moved towards and away from the work by means of a lever 87 which is pivoted to the pivotal indicator supporting bracket 74 and has a slot and pin connection 87 with the indicator slide 79. 'lhe indicator slide 79 is provided with an adjustable stop comprising a screw 88 threaded through a bushing 89 press litted in a bore in a depending lug 90 at the rear end ot' said slide with the inner end of said screw in abutting relation to the pivoted supporting bracket 74. The stop screw 88 is adjusted by means of a knurled knob 91 at the outer end thereof and has a knurled lock collar 92 threaded thereon for locking said screw in the desired adjusted position. By this arrangement, the work engaging arm of the contact lever 86 of the indicator 81 may be brought into the same position with rela-tion to the worm each time the indicator supporting slide 79 is -slid in the direction of the worm.

The indicator is moved longitudinally of the work by rotating the lead screw 68; and the amount of said movement is indicated by a scale 93 marked on the front face of the bracket 65 which slidably supports the indicatorcarriage 69 and by a collar 94 fixed to said screw and provided with graduations adapted to register with a zero mark 95on said bracket. In the prese-nt machine, the

lead screw 68 is provided with' forty threads sponding to the space between adjacent graduations will cause the carriage to move one thousandth of an inch.

The operation of the machine -is as follows: lhe worm that-is to be tested is placed between the dead centers 5 and6 of .the head and tail-stocks 7 and 8, respectively, andsaid tail stock adjusted to bring the two dead centers into engagement with the conical revcesses provided therefor in the ends ofsaid worin. The driving dog 62 is then clamped von ythe worm, thereby connecting the worm to the driving plate 51. The bottom slide plate 35 is set at an angle corresponding to the lead angle desired for the worm lthat is to hetested by rotating the handle 45, which turns the disk 37 that supports Said bottom i. slide plate, until the pin 47 on said disk has,`

tion opposite the forward end of the thread moved far enough away from the pin 46 on the bed 3 to permit the .holes in a link 48 marked with the lead selected to lit over said pins. The driving plate 51 is then connected to the indexing plate 23 by means lot the indexing pin 53. When testing singletlireaded worms'the indexing pin 53 is engaged with any one of the three series of holes 59, 60 and 61 in the indexing plate 23. The indicator 81 is then brought into aposiof the worm by rotating the lead screw 68; and the arm 85 is then swung about the axls of the indicator stem 82 to bring the 'contact arm of the bent contact lever 86 into a position at right angles to the spiral angle of the thread, which lever is then locked in sald position by means of the knurled collet 85a.

The bracket 74, which slidably supports the' indicator, is then swung on its plvot 72 so that the work engaging surface of the contact arm of the indicator will slide ina direction substantially lparallel-to the pressure angle or side of the thread wvhen"the.,.lever 87 is actuated. The indicator isthen shifted transversely of the work axis by'gjrmeans of the lever 87 to bring the Contact point -into engagement with the side of lfthe 'forward end of the thread atl the pitchfline. The 'stop lscrew 88 isthen adjusted to cause the con.-

tact arm of the indicator tol stopatthe ipitch is then locked in such ositionof adjustment by means ofthe .knur ed lock collar 92,'fand the pointer of the indicator is then set lat zero.

After setting the machine as above described, the operation of testing the lead of the single thread worm. is as follows: The indexing disk 23 is rotated one com lete revolution by means of the hand whee 16, which operation also causes the tubular head stock spindle-24, -thedriving disk 51 and the worm to rotate one complete revolution. This 1rotary movement of the head stock spindle 24, by reason of its rack and pinion connection 28, 27 with the top slide plate 29, causes said slide plate to `slide transversely ot' the spindle axis, which movement of said top slide plate, by reason of its pivotal connection 33. 34 withthe angularly disposed bottom slide plate 35 causes said bottom slide plate to move at an oblique angle to the worm axis and thus moves the carnage 1 and the worm thereon in a directionparallel to said axis; whereupon the rotating worm is moved axially during ea-ch complete revolution thereof a distance` corresponding to the lead desired therefor-hud in a direction `opposite to that in` which the thread ad- `vances.

p jf and'l outer surface. line of the worm each tlme said arinj n'sfmoved, into engagement therewlth,A said-stop screwv will remain at zero during this rotary and axial movement of the worm. If there is any variation in the lead the contact lever of the indicator will be actuated, and the indicator will indicate the amount in thousandths lof an inch that the worm is long or short in the lead. After the first ortion of the single thread worm has been c ecked as above described for a distance corresponding to the lead thereof the contact arm of the indicator is disengaged from said thread and the hand wheel 16 is rotated a lreverse direction to return all parts to their original positions. The indicating mechanism is then moved longitudinally of the worm by means ofthe handle 68aL a'distance corresponding tothe lead of the worm and the indicating mechanism operated to cause the contact lever to again vengage the side of the thread at thefpoint where it was removed from the thread after checking the first portion thereof.. vThe next portion of the thread of the worm is then checked for a distance corresponding to the lead thereof; and the operations above described are repeated until the entire thread of the worm has been checked.

', the drawing the index pin 53 is inserted in one of the outer series of holes 59 in the index plate 23, and the first thread is checked for a distance corresponding to the lead of the worm in the manner above described. The parts are then returned to their original positions and the indicating mechanism disengaged from the worm. The index pin 53 is then withdrawn from the index plate, the driving plate 51 reversely lrotated one-half of a revolution and the driving plate again connected with the index kplate by 'inserting the index pin in the hole located diametricallyopposite the hole which was engaged during the checking of the first ".thrcad. This reverse rotation of the driving plate imparts a` similar movement tothe yworm coupled thereto and thus brings the forward end of the second thread into position to be engaged by the contact lever lwithout moving the latter longitudinally of said worm. The contact lever 86 is then moved transversely vof the-worm into engagement with'the side of the second thread which is then checked for a distance corresponding to the lead in the manner described .for the first thread.

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The contact lever is then withdrawn from the. work, the parts are then again returned', 1305i the foregoing it will thus be seen that the indexing pin is engaged'with the outer series of twelve holes when checking one, two, three, four, six, and twelve-thread worms,

the inner series of five holes' is used for checking five-thread worms andthe intermediate series of seven holes is used for checking 'seven-thread worms. j

With the above machine, the accuracy of its setting may be checked in several ways. WVhen the -disk is rotated to bring the bottom slide plate into a position at right angles to the 'axis of the head stock spindle, the distance between the two pins 46 and 47 on one side of the machine should be the same as the distance between the corresponding pins on the opposite side of the machine With the partsin this position, a large disk may be mounted between the dead centers, and an indicator clampedon the base of the machine` with its spindle in engagement with one side of said disk. The disk is then revolved by means of the hand wheell 16. lIf thereis any movement of the indicator dur'- ing this rotation of the disk, it indicates that the pins are out of position or that the bottom slide plate is not at right angles to the axis of the head stock spindle. Another way to check the setting of the machine is to set the bottom slide plate at an angle corresponding toa standard lead angle by measthen mounting between uring over the pins, v

having such standard dead centers a worm lead and then lnoving the indicator into engagement with one side of the thread with the indicator pointer set at zero. The reading on the micrometer on the lead screw 68 is then noted and the indicator is ydisengageil from the worm thread. The lead screw is then rotated the exact distance of the linear pitch of two threads.- The indicator is then brought back into position and should show the same zero reading as before. This would Ishow whether the' pitch is correct.

Then by withdrawing the indicator from the thread once more and continuing the movement of the indicator the full length of the lead andv again bringingthe indicator '.intoengagement with the side of the thread.

, another zero reading of the indicator would show that the lead ,established by measuring over the pins are correct.

Obviously, the hereinbefore described machine admits of considerable modification without departing from the invention; therefore, I do not wish to be limited to the 'precise arrangement shown and described.

What I claim is:

l. A machine for testing the lead of screws comprising means for rotating a screw on itsaxis, means for moving said screw axially during the rotation thereof in .a direction opposite to ythat in which the thread ad- V vances4 and at a rate corresponding to the advance of the thread of a screw having the desired lead, and means engaging the side of `the thread of said screw, whereby inaccuracies in the lead of the screw cause movement of said screw engagin means. 2. A machine for testing t ye lead of screws comprising 'means for rotating a screw on its axis, means for movi-ng said screw axially -.during each completerevolution thereof a distance corresponding to the lead desired for the screw being tested and in a direction opposite to that inv which the thread advances, said means being adjustable to accommodate screws with different leads, and means engaging the side of the thread of said screw, whereby inaccuracies in the lead of the screw cause movement of said screw engaging means.

3. A machine for testing the leadof screws comprising means for rotating a screw on its axis, means for moving said screw axially during the rotation thereof in a direction opposite to that in which the thread advances and at a rate corresponding to the advance of the thread of a screw having the desired lead, and yieldable means engaging the side of the thread thereof, whereby inaccuracies in the'leadof the screwwill cause movement offsaid yieldable screw engaging means. v

4.y A machine for testing the lead of screws comprising means for rotating a screw on its axis, means for moving said screw axiallyduring the rotation thereof in a direction -1 engage the side of the thread of said screw` during the rotation thereof, whereby inaccuracies in the dead of said screw will 'cause movement of said contact arm and thus cause the indicating mechanism to in- .dicate the amount of such inaccuracies.

5. A machine for testing the lead of screws comprising means for rotating a screw on its axis. means for moving said screw axially during the rotation opposite to that in which the threadV advances and at a rate corresponding to the advance of the thread of a screw having the desired lead, an indicating mechanism having a yieldable contact arm adapted to engage the side of the thread'ofsaid screw during the rotation thereof, whereby inaccuracies in the lead of saidscrew will cause movement of said contact arm and thereof in a direction thus'cause the indicating mechanism to indicate the amount that the screw is long o r short iii the lead, and means for adjusting said indicating mechanism'longitudinally of and towards and away from said screw.

6. A machine for testing the lead of screws comprising means for rotating a screw on its axis, means for moving said sciew axially during the rotation thereof in a direction,

opposite -to that in which the thread advances and at a vrate correspondingto the advance of thethread of a screw having the' varices and at arate correspondingto the .in the lead of the screw cause movement of advance of the thread of a screw having the desired lead, means engaging the side ot' the thread of said screw, whereby inaccuracies .in the lead of the screw cause movement of said screw engaging means, and means whereby .said machine is adapted for testing plural threaded screws.

8. A machine vfor testing the lead of Vscrews comprising means for rotating a screw on its axis, means for moving said screw axially during the rotation thereof 'in a direction opposite to that in which the thread ad` vances and at a rate corresponding to the advance of the thread of ascrew having the desired lead, means engaging the side of the thread of said screw, whereby inaccuracies said screw engaging means, means whereby 'i Said machine may be set for any selected lead, Aand means whereby said machine is adapted for testing plural threaded screws.

5 9. A machine -for testing the ylead of. screws comprising means for rotating" y threa'dof said' screwgadvancesyan indicating "screw on its'axis .means for .moving` said screw axially during each completei'evolu-r leaddesiredfortlie screw being tested 1andj;y

inaccuracies in the vleadfof the/worin will tionthereof a distance corresponding to the in a direction opposite to that in which the `thread of said'screw advances,an` indicating device having a yieldable contact arm lalapt- 4ved to engage the side of the thread of said .screw during the rotation thereof, whereby inaccuracies in the lead of the screw willy cause movement vof lsaid contact arm and thuscause the indicating mechanism to in- Ved toengageth screw axially during each complete revolution thereof a distance corresponding to the lead desired for the screw being tested and in a direction opposite to 'that in which thethread of said screw advances, an indicati-ng device having a'l yieldable contact army screw, and means for adjusting said arm for vmovement into and lout of engagement with the thread of said screw in'a plane parallel to thepressure angle'of the thread and pass ing through the axis of'said screw. i

11. A machine for testing the lead -of screws comprising means,4 for rotating a screw on its axis, means for y moving said screw axially during each complete revolution thereof a distance corresponding to the lead desired for the screw being tested and in a direction opposite to tliatin which the thread of said screw advances, an indicating device having a yieldable contact arm adapt'-l ed to engage the side of thethiead of said screw during the rotation thereof, whereby 4inaccuracies inL the llead ofthe worm will cause movement of saidcontact arm and thus causetl'ie indicating mechanism to indicate the aniou'ntof s ucli inaccuracies,- means for moving saidvarm linto and out of engage-v ment `with the lthread of said screw,.and

means for adjusting said indicating mechanism to cause the contact arm thereof to engage'the threadof said screws at thepitch line thereof when said arm is moved into engagement with said screw. i

12. Aimachine forl testingv the lead of screws comprising means vfor Y rotating a screw on its axis/means for 'inoviiig said tion thereof a distancecorresponding to the lead. desired for, the screwbeiiig tested and .in-a direction-opposite to that in 'which the device having a. yi ldablecontact. arm adaptdefof the'thread of said screwd'nring'th a otationlthereof, whereby cause movement of `said-contact .arm and 'thus cause-the indicating'mechanism to indi-4 cate the amount of such inaccuracies, means for moving `said arm into and out vof engagement with the threadl vof said 'r'screw, and

for rotatably supporting a screw, means for 'screw axially' during each complete revoluv lll shifting said (screws,

ing the lead desired for said screw, and an.

indicator mounted on said bed and having a movable contact arm adapted to engage the side of the thread of said screw during the rotation thereof, whereby inaccuracies in the lead of the screw cause movement otl said.

contact arm and thus cause the indicating mechanism to indicate the -amount of such inaccuracies.

14. A machine for testing the lead of screws,lsaid machine comprising a bed, a carriage on said bed provided with means for rotatably supporting a screw,'means for rotating said screw on its axis, means for shifting said carriage on said bed to move the screw axially duringl each complete revolution thereof a distance corresponding to the lead desired for the screw being tested and in a direction opposite to that in which the thread of the rotating screw advances, means for varying riage for screws with different leads and an indicating gage mounted on said bed and having a movable contact arm adapted to .engage the side of the thread of said screw dur- -ing the rotary and axial movement thereof, whereby inaccuracies in the lead of" the screw cause movement of said contact arm and thus cause they indicatingmechanism to indicate the amount of such inaccuracies.

15. A machine for testing the vlead of screws, said machine comprising a bed, a carriage on said bed provided with means for rotatably supporting a screw, means for rotating said screw on its axis, means for carriage on said bed to move the screw axially during each complete revolution thereof a distance corresponding to the lead desired for the screw being-tested and in a direction opposite to that in which the thread ot' the rotating screw advances and at a rate corresponding to the advance ot a screw having the desired lead for the screw being tested, and an indicating gage mounted on said bed and having a movable contact arm adapted 'the thread of' said screw during the rotary and axial movement thereof, whereby inaccuracies in the lead of the screw cause movement of said contact arm and thns cause the indicating mechanism to indicate the amount of such inaccuracies, said carriage shifting means being adjustable to accommodate screws with different leads.

16. A machine for testing the lead of said machine comprising a bed, a carriage on said bed provided with means for rotatably supporting a screw, means for rotating said screw on its axis, means for the movement of said car` to engage the side of' said carriage on said bed to move the screw axially during each complete revolution thereof a distance corresponding to the lead desired for the screw being tested and in a direction'opposite to that in which the thread of the rotating screw advances and at a rate corresponding -to the advance of a screw having the desired lead for the screw being tested, an indicating gage mounted on said bed and having a movable contact arm adapted to engage the side ot' the thread of said screw during the rot-ary and axial movement thereof, whereby inaccuracies in the lead of the screw cause movement ot' said contact arm and thus lcause the indicating mechanism to indicate the amount ot' such inaccuracies, said carriage shifting means being adjustable to accommodate screws with different leads, and means for adjusting said indicating gage longitudinally of the screw axis, towards and away from said screw and in av plane parallel to the pressure angle of the thread of saidiscrew and passing through the axis thereof.,v

17. A machine for testing the -'lead of screws, said machine comprising a bed, a carriage on said bed provided with means for rotatably supporting a screw, a spindle journaled on said carriage for rotating said screw on its axis, means on said carriage for rotating said spindle, means operated by the spindle rotating means for shifting said carriage on said bed to move the screw axially during the rotation thereof in' a direction opposite to that in which the thread of the rotating screw advances and at a rate corresponding to the advance of a screw having the desired lead for the screw being tested, said carriage shifting means comprising a rack geared to said spindle and movable transversely of the axis thereof, a plate shifting mounted on said bed for sliding movement at j an angle corresponding to the lead angle of the screw being tested and a pivotal connection between said rack and said plate,.and means mounted on said bed and adapted to .engage the side ot' the thread ot' said screw during the rotation thereof, whereby lnaccuracies in the lead of the -Screw cause movement of said screw engaging means.

18. A machine for testing the lead of screws, said machine comprising a bed, a carriage on saidbed provided with mea-ns for rotatably supporting a screw, a spindle journaled on said carriage for rotating said .screw on its axis, means on said carriage for rotating said spindle, and meansfor shifting said carriage on said bed. to move the Ascrew axially during the rotation thereof in a direction opposite to that in which the thread of the rotating screw vadvances and at a rate corresponding to the advance of a screw having the desired lead for the screw being tested, said carriage'shifting means comprising a rack geared to said spindle and movable lis transversely of the axisy thereof, a. plate mounted on said bed for slldlng movement at an angle corresponding to the lead angle of the screw being tested, and a pivotal convnection between said rackand said plate.

19. A machine for testing the lead of.

" shiftingmeans comprising a rack geared to said spindle and movable transversely of the axis thereof, a plate mounted on said bed for sliding movement -at an angle corresponding to the lead angle of the screw being tested, and a pivotal connection between said rack and said plate, and an indicator mounted On-said bed and having' an adjustable contact arm adapted to engage the side of the thread of said screw during the, rotation thereof, whereby inaccuracies in the lead ofthe screw cause movement of said contact arm an-d thus cause said indicator to' indicate the amount ofsaid inaccuracies.

E20. A machine for-testing the lead of" screws, said machine comprising abed, a carriage on said bed provided with means for rotatably supporting a screw, a spindle journaled on said carriage for rotating said screw on its axis, meansaon Said carriagel for rotatingV said spindle, means forshifting said carriage on said bed to move the screw axially during each completerotation of said spindl-e a distance corresponding tthe lead desired for 'the screw being tested and in a direction opposite to that in which the thread of the rotating screw advances, said carriage shifting means comprising a rack Ujeared to said spindle and movable transversely of the axis thereof, a plate mounted on said bed for sliding movement at an angle corresponding to the lead angle of the screw being tested, and a pivotal connectlon between said rack and said plate,

means 'for adjusting said indicator longitudinally of the screw axis andvtoward and away therefrom, and means for varying the angular position of said plate to obtain the desired movement .of said carriage.

21. A machine for testing the lead of screws, said machine comprising a bed, a

carriage on said bedprovided with means forrotatably supporting a screw, a spindle journaled'on said carriage for rotating said screw on its axis, means o'n said carriage for rotating said spmdle, means for shlfting said carriage on said bedto move the lscrew axially during the rotation thereof in a direct-ion opposite to` that in which the thread of the rotating screw advancesA and at a rate corresponding to the advance of a screw having the desired lead for the screw being tested, said carriage shifting means comprising Aa rack geared to said spindle and movable transversely of the axis thereof, a plate mounted on said bed for sliding movement at an angle corresponding to the lead angle of the screw being testedl and a pivotal connection between said rack and said plate` means for rotating said plate about the axisof said pivotal connection to varv the angular position thereof, and an indicator mounted on and having a Contact arm adapted to 'engage the side of the thread of said screw during the rotation thereof, whereby inaccuracies 'in vthe lead of the screw cause movement of-said screw engaging means and thus cause the indicator to indicate the amount of said inaccuracies.

2 2. A machine for testing the lead of screws, said machine comprising a bed, 'a

carriage on said bed provided w}th'means 4for rotatably supporting a screw, means on said carriage for rotating said screw on" its axis, said screw rotating means comprising a rotatably supported-spindle, gearing for driving said spindle, a driving plate jour- ,naled on said spindle and adapted to be coupled to said spindle and to said screw, means for shifting said carriage on said bed to movethe screw axially during the rotationl thereof in a direction opposite to that in which the -thread of therotating screw advances and at a rate corresponding to the advance of a. screw having the desired lead for lthe screw being tested, said Carriage .shifting means comprising a rack geared to said spindle and movable transversely of the axis thereof, a plate mounted on said bed for loa@ sliding movement at an angle corresponding to the lead angle of the screw being tested and a apivotal connection between said rack and said plate. and an indicator mounted on said bed and having a contact arm adapted to engage the side of the thread of lsaid screw` during the rotary and axial movement thereof, whereby inaccuracies in the lead of the screw cause movement ofsaid contact arm and thus cause said indicator'to indicate the amount ofv said inaccuracies.: v

'23. A machine for testing the( lead of screws, said machine comprising a bed, a

carriage on said bed provided with meansy for rotatably supporting a screw,-means on said carriage for rotating said screw on its axis. means on said carriage 4fol rot-ating said spindle, said screw rotating means comprising a rotatably supportedfspindle havingv an index plate rigid therewith, a drive platev journaledpn said .spin'dle-a-ndh-adapted to be coupled -to said screw,`said drivel plate being provided with a seriesof circularly INI- noemen with said index plate, means for shiftingl said carriage on said bed to move thescrew.

` axially during the rotation thereof 'in-a directionvv opposite 4to that in which the thread of the rotating screw advances and ling to the advance ofv a screw at a rate corresponding to the advance of a screw havin the desiredlead for the screw being teste said carriage shifting means (comprising a rack geared to'lsaid spindle and movable transversely of the axis thereof, 'a plate mounted on said bed 4for sliding movement at an angle correspondin t'o the lead angle of the screw being teste anda pivotal 'connection between said rack and `said plate, and an indicator mounted on said bed and having a contact arm adapted to engage the side" ofthe thread of said screw duringv the vrotation thereof, whereby inaccuracies in the lead-of the screw cause movement of said contact arm and thus cause said indicator to indicate the amount of said inaccuracies.

24. A machine for testing the le-ad ci screws, said machine comprising a bed, av carriage on said bedprovided with means for rotatably supporting a screw, said carriage for rotating said spindle, said screw rotating means comprising a rotatably supported indle having an index plate (plate journaled on and adapte to be coupled to said spindle plate beingI rovided said screw, said drive with a series of'circularly arran spring .geared to said sp versely1 of the axis said indicator being slidably `means on.

holes, a

drive p ate` and adapted to beengagedwith any one of the holes in said index plate to cause the ydrive plate to rotate with said inpressed index plate mounted on said* dex plate, ,means for shifting said carriage on said bed "to move the screw axially during site to ing screw advances and'at a rate thatin which the thread of the rotatcorresponddesired lead for' the screw being tested, said carriage shifting means comprisin a rack indle and movab e l.transthereof, a plate mounted on said bed for sliding movement at an angle 4corresponding to the lead angle of the screwA being tested, and a pivotal eonnec-Z tion between said rackLand said plate,'-an indicator mounted on said bed and having a contact arm adapted to engage the side A of the thread of said screw during the rotation 'thereef, whereby inaccuracies in the lead of the. screw cause movement of said contact armand thuscause said indicator to indicate the amount of said inaccuracies, supported for movement towards and away from the work on a bracket pivotally sup orted on a 'carringe `slidable on said be yinI a direction parallel to the spindle axis, anda lead screw journaled on said bed and operatively en gaging the indicator carriage for actuating thesame.

Signed at Detroit, Michigan, this 2nd day o f May; 1927.

PERCE E.r GanLEN'r.

the rotation thereof in a direction oppohaving the 

